Gestalt kineticist ideas

[Railak]

So I'm building a geokineticist for a gestalt campaign I'm just not sure what to pair with it. He's supposed to be the tanky one if the group oh yeah, using the legendary kineticist if anyone is wondering. Anyone got suggestions, aside from dropping kineticist, it's a required class for the campaign.

[Psyren]

Kineticists have multiple problems (https://forums.giantitp.com/showthread.php?614578-Kineticist-Problems-did-I-find-them-all), but the most pertinent to you as a gestalt geokineticist are:

1) Most (all?) earth blasts are physical, so your biggest pain point will be your low attack bonus (3/4 BAB) since you'll be targeting regular AC on most monsters. Your only in-class boost to this comes from Elemental Overflow (see below).

2) Even when you do manage to hit, your physical blasts are subject to other defenses like DR, incorporeal and regeneration unless you use costly infusions. Earth Blast lets you seamlessly switch between the three main physical types (B/P/S) which helps out a lot early on, but as you level you increasingly come across material-based DR/regen like cold iron, silver and adamantine - and you pretty much never overcome incorporeal (your blast counts as magic so you at least do half damage.) This can result in a lot of wasted actions as you gain levels.

3) Your Kinetic Blast only counts as a weapon for the purposes of feats, so your second class needs abilities that boost all attacks you make without being tied to a specific weapon. There are also few to no magic items that will assist you, so classes that excel at crafting won't help much either.

4) Elemental Overflow is the tool intended to help with your low to-hit and damage - but using it means you need to run around all day carrying a degree of burn (heh). This effectively eats into your maximum hit points, and also limits the burn you have available to do utility things with. So you need a secondary class that can fight effectively without incurring more burn, and ideally one that can do things outside of a fight too so that you're not dependent on wild talents that will eat up your remaining burn and/or put you at risk of getting knocked out.

Combining all these issues gives you some principles to keep in mind as you select a secondary class:

1) Full BAB to help land blasts
2) d10 or d12 HD to help carry burn (these first two go hand-in-hand usually so that helps.)
3) Weapon-agnostic attack bonuses (e.g. Favored Enemy, not Weapon Training)
4) Other ways to attack (vs. enemies where your blasts will be ineffective)
5) Out of combat utility
6) High will-save - this is the least important (having one weak save isn't a dealbreaker, but if you can cover it then go for it.)
7) Avoid Size bonuses (e.g. shapeshifting) - these won't stack with your Elemental Overflow.

With all those principles in mind here are some suggestions:

1) Fighter (Mutation Warrior) - This gets you d10 and full BAB, bonus combat feats (both weapon-specific and general-purpose archery are good here), and most of all a nice Dex or Con mutagen for big bonuses (bigger with your mutagenic discoveries) as needed. Weapon Training is useless so consider dropping it via Martial Master for even more combat feats, or pick up some Advanced Weapon Trainings for things like more skills or Item Mastery.

2) Barbarian (Urban) - d12 HD, concentrate while raging, and you get to apply your rage bonuses to both Dex and Con to be even better at what you do.

3) Bloodrager (Urban) - see above, with more utility from spells and bloodline powers. Good thematic synergy here if you take a bloodline like Elemental, and can be combined with Primalist to swap out weaker bloodline powers for useful rage powers.

3) Ranger - Tailor your Favored Enemy to things you'll face in the campaign, and use Instant Enemy for outliers. d10 HD, lots of skill points, and utility magic here.

4) Slayer - While Sneak Attack is helpful, Studied Target is useless to you so you'll want an archetype that replaces it. Dune Rider and Avalancher seem thematically appropriate, but I'm less familiar with this class so there may be better suggestions. As with Ranger, the skill points here will help you from a utility perspective.

[Railak]

Great breakdown of all the issues, and I've been thinking mostly about fighter or barbarian. The only flaw I saw in your breakdown is legendary kineticist is a little different.. the burn doesn't deal non-lethal damage, it gives penalties on str and dex checks.